Process for the treatment of waste soda liquors.



- UNITED STATES PATENT oFF o.

VIGGO DREWSEN, OF BROOKLYN, NEW YORKgASSIG-NOR TO WEST VIRGINIA PULP & PAPER COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

PROCESS FOR THE TREATMENT OF WASTE 'SOPA LIQUORS- No Drawing. Application filed June 10, 1914,

To all whom it may concern Be it known that I, Vrooo DnnwsnN, a c1t1- zen of the United States, and resident of the borough of Brooklyn, county of Kings, city and State of New York, have made a certain new and useful Invention Relatin Processes for the Treatment of Waste oda Liquors, of which the following is a specification.

This invention relates especially to the treatment of waste liquor wh1ch is commonly known as black liquor produced especially when paper pulp is manufactured from deciduous woods, such as poplar or from other similar acting material such as straw, fiax, and so forth, by the caustic soda process. The waste soda liquor may with advantage be first delignated by having the greater proportion of its dissolved or suspended woody material precipitated by the action of carbondioxid preferably under conditions of heat and pressure and the delignated liquor may be filtered from this precipitate and causticized with powdered quic (lime preferably after further concentration. The proportion of lime is preferably such as to produce substantially dry powdered, lime organic material which preferably is treated with carbon-dioxid and moisture to aggregate the lime particles and then' after heating to 160 degrees or more if desired, the causticized material may be leached with cold water to dissolve without undesirable admixture the sodium acetate which may be separated by evaporation, crystallization and so forth.

In carrying out this process the soda waste liquor is preferably concentrated so that it contains not more than about sixty (60) per cent. of water, say only about 50 per cent. of water so as to have a specific gravity of about 1.28. This concentrated waste liquor in which the organic compounds or ligneous material are dissolved or suspended may be first heated to a temperature of 70 to 90 degrees centigrade or thereabout and then treated under suitable ressure with carbondioxid until it is su stantially saturated therewith. Good results may be secured by maintaining a pressure of 50 to 100 pounds per square inch during this ligneous precipitation process which seems to precipitate from this concentrated liquor the bicarbonate of soda and woody or organic material which when sufiicient heat and pressure are Specification 01. Letters Patent.

Patented Mar. 25, 1919.

Serial No. 844,254. Renewed August 10, 1918. Serial No.

material by steam distillation or various other recovery processes so as to secure valuable oils, solvents and other material.

The filtrate or delignated waste liquor which usually has a dark-or black color somewhat similar to the original black liquor may with advantage be further concentrated to about half its original weight and then mixed or inconporated with powdered or finely divided quicklime to the extent of about 50 per cent. of its weight so as to secure a vigorous reaction as this quicklime is slaked while in intimate contact with the-delignated waste liquor and generates considerable heat which in some instances may be retained to exert a desirable action on the treated material by promoting combination between the lime and organic material. Suitable agitation should be maintained during this reaction to prevent settling and promote uniform conversion of the organic compounds into more insoluble form in this lime organic material. The proportion of quicklime used in this causticizing treatment is so proportioned in connection with the amount of water in the concentrated liquor that by chemical absorption and evaporation practically all of the sensible water or moisture is driven off and a causticized substantially dry powder is produced in which the lime seems to have combined more 'or less with the remaining organicmaterial.

It seems desirable in order to facilitate the subsequent filtration to get the lime into the form of larger particles and this may be effeted by further treatment with carbondioxid has been allowed to bubble up through water or be otherwise moistened to facilitatethis aggregating action. This carbon-dioxid treatment need not, however,- be carried to complete alkaline material, but only far enough to remove the objectionable finencs o the slaked lime which is usuall present .1111 excess. It also seems desira le to heat the resulting substantially dry material at a suitable high temp complete the reactlon between the lime and the organic components as is evidenced by the evolution of some volatile organic material during this part of the process. The material may be heated to about 160 to 200 degrees centigrade or so for about an hour whlch seems to give good results with black soda pulp liquor resulting from the treatment of poplar wood, for instance.

The heated causticized mixture is now leached out with cold'water of sufiiciently low temperature so as not to dissolve undesirable organic components to an objectionable extent. Good results can be secured promotes this leaching when this leachin water is at a temperature of about ten to fi en degrees centigrade or less and it is of course undesirable to use an unnecessarily large amount of this leaching water or other liquid. While agitation rocess it is not usually necessa since t e water may be allowed to perco ate through the causticized material in a percolator or the like,-giving a brownish tinged or coffee colored liquid which contains a large proportion of sodium acetate. By concentrating the leaching liquor the sodium acetate may be recovered in crystalline form as by cooling the concentrated liquor to about 0 centigrade or so, the concentration and crystallization being repeated as necessary; and the crystals may be subjected to the usual purifying processes, if desired. In this way by first separating the large proportion of the woody material from the waste soda liquor, the sodium or other acetate material may be effectively recovered in large quantities from the delignated liquor, without destruction or waste of these valuable components during the other recovery processes to which the precipitated ligneous material maJy be subjected.

This invention has been described in con! nection with a number of illustrative ingredients, temperatures, pressures, conditions, and character and order of steps, to the details of which disclosure the invention is not of course limited.

What is claimed as new and what is de-' sired to be secured by Letters Patent is set forth in the appended claims:

1. The process of treating the waste soda liquor produced in the manufacture of wood pulp from poplar wood by the soda pulp process, which consists in concentrating the waste liquor by evaporation until the proportion of water in the concentrated may neutralization of the erature which seems to' cized substantially dry,

' bon-dioxid while heating the liquor under pressure to promote the collection "of the precipitated material, in filtering the treated'liquor to separate from the precipitate the delignated waste liquor, in concentrating the said delignated waste liquor and incorporating therewith about half its weight of powdered quicklime to produce causti powdered, lime oranic material, in aggregating the hydrated ime particles by treatment with carbondioxid and moisture, in heating the treated causticized material to about 160 to 200 degrees 0., in leaching said causticized material with relatively small proportions of cold water to leach out the sodium acetate free from interference by undesirable organic material and in concentrating and separatin by crystallization sodium acetate from the caching liquor.

2. The process of treating the waste soda liquor produced in the manufacture of wood .pulp from deciduous wood, by the soda pulp process, which consists in concentrating the waste liquor by evaporation until the proportion of water in the concentrated material is not more than about sixty per cent,

in delignating the'waste liquor by largely precipitating therefrom the ligneous material and sodium with carbon-dioxid while heating the liquor under pressure to promote the collection of the precipitated material, in filtering the treated liquor to separate from the precipi tate the delign'ated waste liquor, in concentrating the said delignated waste liquor and incorporating therewith quicklime to produce causticized substantially dry, powdered, lime organic material, in heating the treated causticized material to about 160 to 200 degrees C., in leaching said causticized material with relatively small proportions of cold water to leach out the sodium a'cetatefree from interference by undesirable organic material and in concentrating and separating by crystallization sodium acetate from the leaching liquor.

bicarbonate by treatment 3. The process of treating the waste soda liquor produced in the manufacture of wood pulp from deciduous wood by the soda pulp process, which consists in' concentrating the waste liquor by evaporation until the proportionof water in the concentrated material is not more than about sixty per cent., in delignating the waste liquor by largely precipitating therefrom the ligneous material and sodium bicarbonate by treatment with carbon-dioxid while heating the liquor under pressure to promote the collection of the precipitated material, in filtering the treated liquor to separate from the precipiweasel tate the. delig' naited waste liquor, in concentrating the said delignated waste liquor and incorporating therewith quicklime to roduce causticizcd lime organic materia in leaching said cuusticizcd material with relatively small proportions of 'cold water to leach out the sodium acetate free from interference by undesirable organic material and in concentrating and separating sodium acetate from the leaching liquor.

4. The process of treating the waste soda liquor produced in the manufacture of paper pulp from deciduous wood by the soda pulp process, which consists in concentrating the waste liquor until the pr drtron of water in the concentrated materlal is only about fifty per cent. in delignating the waste liqu'or by largely precipitating the ligneous material therefrom without eliminating the acetate material therefrom, in concentrating the delignated waste liquor and incorporating therewith about half its weight of powdered quicklime and heating the mixture to produce causticized substantially dry, powdered, lime organic material, -in leaching said causticized material with relatively small roportions of cold water to leach out the sodium acetate free from interference by undesirable organic material and in recovering by evaporation and crystallization sodium acetate from the leaching liquor.

5. The process of treating the waste soda liquor produced in the manufacture of paper pulp from deciduous wood by the soda pulp process, which consists in concentrating the waste liquor until the proportion of water in the concentrated material is only about fifty per cent., in delignating the waste liquor by precipitating ligneous material therefrom without eliminating the acetate material therefrom, in concentrating the delignated waste liquor and incorporating therewith quicklime and heating the mixture to produce causticized substantially dry, lime organic material, in leaching said causticized material with relatively small proportions of cold water to leach out the sodium acetate free from interference by undesirable organic material and in recovering sodium acetate from the leaching liquor.

6. The process of treating the Waste soda liquor produced in the manufacture of cellulose from vegetable fiber material by the Soda process, which consists in concentrating the waste liquor, in delignating the Waste liquor without eliminating the acetate material therefrom, in concentrating the delignated waste liquor and incorporating therewith quicklime to produce causticized lime organic material, in leaching said causticized material to leach out the sodium acetate free from interference by undesirable organic material and in recovering sodium acetate from the leaching liquor.

7. The process of treating the waste soda liquor produced in the manufacture 'of paper pulp from deciduous wood such as poplar, etc., by the sodap'ulp process, which consists in delignating the waste liquor by largely precipitating the ligneous material therefrom by treatment with carbon-dioxid while heating the liquor under pressure to promote the collection of the precipitatedmaterial, in concentrating and camstrcizing with lime the delignated waste liquor to produce causticized substantially 'd lime organic material, "in aggregating the hydrated lime particles by treatment with. carbondioxid and moisture, in heating the treated oausticized material to about 160 to'200 degrees 0., in leaching the said causticized material with relatively small proportions of cold Water to leach out sodium acetate free from interference by undesirable organic material and in recovering sodium acetate from the leaching liquor.

8. The process of treating the waste soda I liquor produced in the manufacture of paper pulp by the soda pulp process, which consists in delignating ;the waste liquor, in concentrating and causticizing with lime the delignated waste liquor to produce causticized substantially dry, lime organic material, in leaching the said causticized material with relatively small proportions of cold water to leach out sodium acetate free from interference by undesirable organic material and in recovering sodium acetate from the leaching liquor.

9. The process of treating the waste soda liquor produced in the manufacture of paper pulp by the soda pulpuprocess, which consists 1n delrgnating the waste liquor, in concentrating and caustioizing the delignated waste liquor, in leaching the causticized material to leach out sodium acetate and in recovering sodium acetate from the leaching liquor.

10. The process of treating the waste soda liquor produced in the manufacture of paper pulp from deciduous wood by the soda pulp process, which consists in concentrating and delignating the waste liquor, in concentrating and causticizing with lime the delignated waste liquor and in leaching out therefrom with cold water sodium acetate free from interference by undesirable organic material.

11. The process of treating the waste soda liquor produced in the manufacture of paper pulp by the soda pulp process, which consists in concentrating and delignating the waste liquor, in concentrating and causticizing the delignated waste liquor and in leaching out therefrom sodium acetate free from interference by undesirable organic material.

12. The process of treating the waste soda liquor produced in the manufacture of cellulose by the soda process which consists in delignating the waste liquor, in concentrating and causticizing the delignated waste liquor and in leaching out the refrom sodium some of the organic materialtherein and reacetate frecfrom substantlal interference by ducing its solu llii'g' to subsequent undesirable organic material. interference of are organic material and in 13. The rocessoftreat' the waste soda leaching the treated material to leach out 5 liquor p uced inthe manu acture ofeelluacetate therefrom. 2o

lose from deciduous-wood by the soda proc- 15. The rocess of the waste soda ess which comprises concentrating sud caushquor'p need in the manu actureof celluticizing the waste liquor and leaching out lose by the soda process which consists in I therefro acetate interference by causticizingand partially 'dehgnsting the 10 undesirable orgamcmaterlal. waste liquor and in leaching out acetate 25 14. Thgfrocess of treating the waste soda I therefrom. a liquor pr need in the manufacture of cellu- VIGGO DREWSEN. lose from vegetable fiber material by the -Witnesses: caustic process which comprises eoncentrat- Hem L. Duncan,-

15 ing thewaste liquor and chemically changing 'Jsssm B. KAI. 

